Income Taxes Deferred income tax provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Components of deferred tax provision [Line Items]
Deferred Income Tax Expense (Benefit)	$ (2,508)	$ 3,942	$ (1,198)
Allowance for Doubtful Accounts [Member]
Components of deferred tax provision [Line Items]
Deferred Income Tax Expense (Benefit)	0	0	4
Inventory Valuation Reserve [Member]
Components of deferred tax provision [Line Items]
Deferred Income Tax Expense (Benefit)	(162)	284	(488)
Accruals other [Member]
Components of deferred tax provision [Line Items]
Deferred Income Tax Expense (Benefit)	(2,599)	(2,977)	(1,326)
State and Local Jurisdiction [Member]
Components of deferred tax provision [Line Items]
Deferred Income Tax Expense (Benefit)	61	502	(4)
Acquired future tax deductions [Member]
Components of deferred tax provision [Line Items]
Deferred Income Tax Expense (Benefit)	1,520	3,139	96
Depreciation and Amortization [Member]
Components of deferred tax provision [Line Items]
Deferred Income Tax Expense (Benefit)	(2,544)	1,080	(780)
Operating Income (Loss) [Member]
Components of deferred tax provision [Line Items]
Deferred Income Tax Expense (Benefit)	(2,256)	195	62
Tax credits [Member]
Components of deferred tax provision [Line Items]
Deferred Income Tax Expense (Benefit)	(873)	(635)	1,238
Valuation Allowance of Deferred Tax Assets [Member]
Components of deferred tax provision [Line Items]
Deferred Income Tax Expense (Benefit)	$ 4,345	$ 2,354	$ 0